Electrical connectors or modular jacks for telecommunications and data transmission system connectors are disclosed in U.S. Pat. No. 4,648,678 to Archer and U.S. Pat. No. 5,061,209 to Bolick. However, such connectors have limited performance capabilities, particularly for high performance data transmission at higher frequencies, i.e., greater than 1 MHz. Performance characteristics, particularly near end crosstalk, degrades at these higher frequencies.
When an electrical signal is carried on a signal line which is in close proximity to another signal line or lines, particularly adjacent contacts in a connector, energy from one signal line can be coupled onto adjacent signal lines by means of the electric field generated by the potential between two signal lines and the magnetic field generated as a result of the changing electric fields. This coupling, whether capacitive or inductive, is called crosstalk when this phenomenon occurs between two or more signal lines.
Crosstalk is a noise signal and degrades the signal-to-noise margin (S/N) of a system. In communications systems, reduced S/N margins result in greater error rates in the information conveyed on a signal line.
One way to overcome this crosstalk problem is to increase the spacing or the shielding between the signal lines. However, in many cases, the contact geometries are defined by standards for interchangeability with mating connectors, making changes in the connector contact geometries unavailable. The connector standards have existed prior to the need for high speed data communications.
These standards have created a large installed base of installed connectors and a need for connectors capable of meeting the requirements of today's high speed communications, while maintaining compatibility with existing connectors. Conventional connectors experience a great deal of crosstalk at the higher signal frequencies.